Researchers at City University of New York (CUNY) have published their research findings on an unusual way of storing information - in diamonds!Their research focusses on using the diamond structure 'nitrogen vacancy' to write data in 3D:
Leveraging on the singular dynamics of NV− ionization, we encode information on different planes of the diamond crystal with no cross-talk, hence extending the storage capacity to three dimensions.
(excerpt from Abstract of the research paper)
This 3D capability greatly enhances the memory storage capacity compared to other conventional methods such as hard disk drives.
Although people would imagine the cost would be an issue. However, considering that data would be the currency of the future and that the amount of data increases every day, maybe this would a viable option considering the opportunity cost of space utilised for memory storage.
You can read the full paper here.